Charter for Working Group

The object of this group is to develop specifications for using forward error correction (FEC) codes with applications in the Internet to provide protection against packet loss. The group will develop a protocol framework for application of FEC codes to arbitrary packet flows over unreliable transport protocols over both IP multicast and unicast. The application of the FEC codec on an aggregate of multiple packet flows may be investigated and considered to be included in the solution.

The FECFrame working group will use the building block approach (RFC 3269), especially the FEC Building Block (RFC 3452), developed by the RMT working group. The FEC Building Block was developed to ensure that the RMT framework developed can support multiple FEC codes and maintain independence between FEC codes and protocols based on the framework. The FECFrame WG may develop new FEC schemes if necessary to provide substantial performance gains for the intended applications. However the acceptance of any FEC scheme will require multiple, prior, detailed reviews of the FEC code by independent experts from both the IETF and the broader community, since it is likely that the IETF working group will not include a large enough number of suitable experts in its working set. If these reviews are positive, then Working Group acceptance of an FEC scheme work item still needs the approval of the responsible Area Director.

A primary objective of this framework is to support FEC for real-time media applications using RTP over UDP, such as on demand streaming and audio/video broadcast. Other potential usages of the framework may be brought to the working group for consideration during the development of the requirements, to enable future support of those usages. The group will coordinate closely with the AVT and MMUSIC working groups to ensure that the streaming use-case is fully specified both in terms of interactions with RTP/RTCP and application layer signalling. The group will also coordinate with the DCCP working group, at least to consider that transport protocol's role in streaming media. The interactions of the framework with existing and used security mechanisms must also be considered.

The group will work with the RMT working group to ensure that the FEC Building Block defined in RMT supports both the RMT use-cases (object delivery over multicast) and the more general FEC protection of flow(s) over unreliable unicast and multicast transport.

Specification of hybrid schemes involving both retransmission and forward error correction is out of scope of the group.